Hi Vlad:
Thanks for getting in touch. We have all the time in the world to help anyone who says they like our product!
For questions about building plug-ins, we take them here on this email forum, and also on the GitHub forum.
For your points:
1. I have cc'd the engineers that have spent the most time either architecting the plug-in framework, and / or using it to build our plug-ins especially the Java / Maven ones.
2. As a general rule, the objective is to be able to plug existing libraries for various languages to run natively within the workspace, and then to create Che plug-in wrappers around those libraries, turning them into RESTful services. This is what was done for Java, and some _javascript_. I believe that our abstractions are clean here, but I imagine that the cleanliness of the abstractions themselves get stronger as more languages are added in. I am just the project lead, not the architect - so those CC'd can provide better descriptions.
Could you share a little about which languages you'd like to add support for?